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Aft Holding Tank

Posted: September 3rd, 2019, 9:58 pm
by Peter3607
Question: my '89 3607 aft cabin has a holding tank under the bed and under the foot of the bed is the vent filter.
My wife notices the odour of the holding tank in the aft cabin. I notice it sometimes.

I'm wondering what could be causing the odour to leak into the cabin? Could the vent filter need replacing? I drop sewage tank treatment pods into the toilet every week but this doesn't seem to resolve the odour. I also have an automatic air freshener to help mask the odour.

Anyone have some ideas?

Re: Aft Holding Tank

Posted: September 3rd, 2019, 11:11 pm
by waybomb
Take a damp rag. Rub the waste hose. Smell the rag. If you smell it on the rag, your hoses need changing.

Re: Aft Holding Tank

Posted: September 4th, 2019, 6:42 am
by Viper
What Fred said. If your hoses are original, 30 years is well past their time. If you don't get an odour on the rag as mentioned above, I like using a hot wet rag and leaving it on the waste hose for 15 minutes. That will tell you for sure if they need replacing. If you have a plastic holding tank, use a different rag on the tank, some plastics are more permeable than others.

The vent filter is for reducing the odours released through the tank vent on the outside of the hull. Unless you're getting a back-draft of that odour through an open window, that's the only way vent odours would enter your cabin space providing you don't have a system leak.

Keep us posted

Re: Aft Holding Tank

Posted: September 4th, 2019, 7:10 pm
by Peter3607
When you guys say to put a wet rag on the waste hose, do you mean the hose leading into or out of the tank?
And by the way, I have stainless steel holding tanks.

Re: Aft Holding Tank

Posted: September 4th, 2019, 7:29 pm
by bud37
Peter3607 wrote:Source of the post When you guys say to put a wet rag on the waste hose, do you mean the hose leading into or out of the tank?
And by the way, I have stainless steel holding tanks.



Hot wet rag like the guys said......then take outside and sniff, you will know one way or the other.....check both hoses and considering you have a SS tank, have a real close look at the welds and seams for any signs of corrosion, pinholes or leakage.

Re: Aft Holding Tank

Posted: September 4th, 2019, 8:38 pm
by km1125
Someone must have replaced your tanks, as I think all the original tanks were plastic. Are your water tanks plastic?

When you say "the foot of the bed", do you mean the end closest to the aft cabin door, or the transom end? I don't have any access to the "cabin door" end of the berth, so if there was a filter on that end I'd have to remove the whole top to get to it. The transom end has two access panels and then there is a smaller one over the water heater.

Re: Aft Holding Tank

Posted: September 4th, 2019, 8:44 pm
by Viper
Peter3607 wrote:Source of the post When you guys say to put a wet rag on the waste hose, do you mean the hose leading into or out of the tank?....

The hose from the toilet to the tank. Try to get to a low lying section. If you have an electric toilet, this is the hose that will always have waste in it at all times. This is what leads to permeation and odour.

Re: Aft Holding Tank

Posted: September 4th, 2019, 10:03 pm
by vineyardgray
Is it for sure sewage you're smelling? Is is maybe bilge funk that is wafting over you?

Re: Aft Holding Tank

Posted: September 6th, 2019, 8:01 am
by Viper
I agree, could also be the bilge, shower sump, etc.

Re: Aft Holding Tank

Posted: September 6th, 2019, 4:40 pm
by Peter3607
So I did some further investigation and found a floor cover leading to the bilge outside the shower with the sump pump and some water in the bilge. Yes this did have that hint of sewage odour to it. I will clean it out this weekend and try to deodorize it and see what happens. I hope this is the simple solution.